Low-dose naltrexone (LDN) is being increasingly researched and prescribed for chronic pain management. Naltrexone is an opioid receptor antagonist and is primarily used in the treatment of opioid addiction. In the setting of opioid addiction treatment, an average dose of naltrexone is 50–100 mg daily. Alternatively, LDN is a much smaller daily dose of naltrexone. In most research, the daily dosage is 4.5 mg, but dosing is patient-specific and may be slightly lower or higher (Marcus, Robbins, Araki, Gracely, & Theoharides, 2024). At this lower daily dosing, naltrexone has been shown to exhibit paradoxical effects, particularly analgesic and anti-inflammatory effects, which have not been reported at higher daily dosages of naltrexone (Younger, Parkitny, & McLain, 2014).

LDN works through modulation of neuro-inflammation and the release of inflammatory chemicals in the central nervous system (Kim & Fishman, 2020). Some notable pros of LDN are that it generally has low side effect potential, with the most frequently reported side effect being vivid dreams, and that it has no known abuse potential (Younger et al., 2014). Naltrexone is also a relatively inexpensive medication (Younger et al., 2014). However, a notable con of LDN is that because it is still being researched, it is considered experimental and is not covered by most insurance policies. Because of this, prescriptions for LDN are typically sent to a local compounding pharmacy, which will then prepare the medication individually for the patient. Every compounding pharmacy will have different pricing for LDN.

There is promising evidence suggesting that LDN could be beneficial in the treatment of chronic pain, including chronic pelvic pain. Many individuals who have endometriosis experience chronic pelvic pain that is often multi-factorial, with refractory pelvic floor spasm and pelvic floor dysfunction. Some patients with very long-term symptoms also struggle with nociplastic pain (or central sensitization). Evidence supports that LDN can be considered as a possible treatment option in the setting of chronic pelvic pain.

There is a lot of discussion in mainstream media about the role of LDN in chronic inflammation and pain management. This is significant in the world of endometriosis, since endometriosis causes both chronic inflammation and pain! While LDN is not right for everyone, it might be considered in the treatment plan of some patients with endometriosis. At Pacific Endometriosis and Pelvic Surgery, we are committed to continuing education to stay current with advances in clinical research and evolving healthcare practices. We hope there is more published research specifically into the potential role of LDN in endometriosis, adenomyosis, and pelvic pain management in the future.

References

Kim, P. S., & Fishman, M. A. (2020). Low-dose naltrexone for chronic pain: Update and systemic review. Current Pain and Headache Reports, 24(10), 64. https://doi.org/10.1007/s11916-020-00898-0

Marcus, N. J., Robbins, L., Araki, A., Gracely, E. J., & Theoharides, T. C. (2024). Effective doses of low-dose naltrexone for chronic pain – An observational study. Journal of Pain Research, 17, 1273–1284. https://doi.org/10.2147/JPR.S451183

Younger, J., Parkitny, L., & McLain, D. (2014). The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain. Clinical Rheumatology, 33(4), 451–459. https://doi.org/10.1007/s10067-014-2517-2